Bacterial contamination of intravitreal needles by the ocular surface microbiome

PurposeThe ocular surface microbiota are recognised as one of causative microorganisms in post-procedural endophthalmitis but in many cases the vitreous tap is culture negative. This study investigated bacterial contamination of intravitreal (IVT) needles using multiple approaches covering culturing, 16S rRNA gene sequencing, fluorescent in situ hybridisation (FISH) and scanning electron microscopy (SEM).MethodsIVT needles were obtained immediately after injection from patients undergoing treatment for predominantly age-related macular degeneration. Eighteen needles were analysed by culturing on chocolate blood agar. In addition, 40 needles were analysed by extracting DNA and paired-end sequencing of the 16S rRNA gene. Sequences were quality filtered (USEARCH), taxonomically classified (SILVA) and contaminant filtered (DECONTAM). Nine needles were analysed by either FISH using the bacterial probe EUB338 or SEM.ResultsUsing culturing, three bacteria were identified from 5 of 18 needles (28%) - Kocuria kristinae, Staphylococcus hominis and Sphingomonas paucimobilis. The negative control needles showed no growth. Following rigorous data filtering, bacterial community analysis using 16S rRNA gene sequencing showed the presence of predominantly Corynebacterium but also Pseudomonas, Acinetobacter, Sphingomonas, Staphylococcus and Bacillus on the needles. Cocci-shaped cells in a tetrad formation were observed using FISH, while SEM images showed cocci-shaped bacteria in pairs and irregular tetrads.ConclusionsThe study showed evidence for a large diversity of bacteria on IVT needles and visually confirmed their adherence. The diversity was similar to that found on the ocular surface and in conjunctival tissue. This suggests the risk of exogenous endophthalmitis remains even with sterilization of the conjunctival surface.     

Ocular surface microbiota in patients with aqueous tear-deficient dry eye

PurposeAn altered ocular surface microbiota may contribute to the pathophysiology of dry eye disease. The aim of the study was to explore potential differences in microbiota diversity and composition in aqueous tear-deficient dry eye (with and without ocular graft-versus-host disease) compared with controls.MethodsSwab samples from the inferior fornix of the conjunctiva were obtained from patients with aqueous tear-deficient dry eye with and without ocular graft-versus-host disease (n = 18, n = 21, respectively) and controls (n = 28). Isolated bacterial DNA from swabs were analyzed with 16S rRNA gene amplicon sequencing.ResultsDecreased microbiota diversity was observed in patients with aqueous tear-deficient dry eye (p ≤ 0.003) who also showed a difference in microbiota composition compared with controls (p = 0.001). Although several genera were less abundant in aqueous tear-deficient dry eye, a minimal core ocular surface microbiota comprising five genera was shared by >75% of the study participants: Enhydrobacter, Brevibacterium, Staphylococcus, Streptococcus and Cutibacterium. Pseudomonas was identified as a bacterial biomarker for controls and Bacilli for patients with aqueous tear-deficient dry eye.ConclusionsOcular surface microbiota in patients with aqueous tear-deficient dry eye was characterized by an aberrant microbiota composition in comparison to controls, with decreased diversity and reduced relative abundances of several genera. Additionally, a few genera were present in most of the study population, indicating that a minimal core ocular surface microbiota may exist.     

Comparison of ocular microbiomes between patients with and without dry eye北大核心CSCD

Objective To explore the difference in ocular surface microbiota between patients with and without dry eye. Methods Forty-two patients (42 eyes) diagnosed with dry eye were enrolled as dry eye group in the First Affiliated Hospital of Xi'an Jiaotong University from June to November 2020, and 37 controls without dry eye (37 eyes) were enrolled as control group in the same period.One eye was selected as the study eye, and the right eye was included when both eyes met the inclusion criteria.Swab samples from the conjunctival sac were obtained and sequenced.Sequencing of the V3-V4 region of the bacterial 16S rRNA gene was performed with Miseq PE301+ 8+ 301 platform.Operational taxonomic species (OTUs) clustering of microflora, comparison of alpha and beta diversity analysis of microflora between the two groups, annotation analysis of species and analysis of microbial markers were performed.The study protocol was approved by the Ethics Committee of The First Affiliated Hospital of Xi'an Jiaotong University (No.XJTU1AFCRC2018SJ-014). Written informed consent was obtained from each subject before any medical examination. Results A total of 18 586 OTUs were obtained, and 3 674 OTUs were shared between the two groups.Alpha diversity analysis showed that there was no significant difference in observed species index, Chao index, Ace index, Shannon index and Simpson index between the two groups (all at P>0.05), suggesting there was no difference in microbiota richness between them.The PCoA analysis showed that the microbial compositions of the two groups were significantly different (R2=0.039, F=3.100, P=0.022). The dominant flora of the two groups was similar, with Proteobacteria, Actinobacteria, Firmicutes, Bacteroidetes and Cyanobacteria as the top 5 abundant bacterial phyla, with Pelomonas, Corynebacterium, Propionibacterium, Pseudomonas and Herbaspirillum as the top 5 bacterial genera.LEfSe analysis identified Tissierellaceae, Enhydrobater and Finegoldia as dominant bacterial genera in dry eye group, and Caulobacter and Curvibacter in control group. Conclusions The composition of ocular surface microbiomes is different between dry eye patients and controls. © 2023 Henan Institute of Ophthalmology. All rights reserved.     

RNA-targeting strategies as a platform for ocular gene therapy

Genetic medicine is offering hope as new therapies are emerging for many previously untreatable diseases. The eye is at the forefront of these advances, as exemplified by the approval of Luxturna® by the United States Food and Drug Administration (US FDA) in 2017 for the treatment of one form of Leber Congenital Amaurosis (LCA), an inherited blindness. Luxturna® was also the first in vivo human gene therapy to gain US FDA approval. Numerous gene therapy clinical trials are ongoing for other eye diseases, and novel delivery systems, discovery of new drug targets and emerging technologies are currently driving the field forward. Targeting RNA, in particular, is an attractive therapeutic strategy for genetic disease that may have safety advantages over alternative approaches by avoiding permanent changes in the genome. In this regard, antisense oligonucleotides (ASO) and RNA interference (RNAi) are the currently popular strategies for developing RNA-targeted therapeutics. Enthusiasm has been further fuelled by the emergence of clustered regularly interspersed short palindromic repeats (CRISPR)-CRISPR associated (Cas) systems that allow targeted manipulation of nucleic acids. RNA-targeting CRISPR-Cas systems now provide a novel way to develop RNA-targeted therapeutics and may provide superior efficiency and specificity to existing technologies. In addition, RNA base editing technologies using CRISPR-Cas and other modalities also enable precise alteration of single nucleotides. In this review, we showcase advances made by RNA-targeting systems for ocular disease, discuss applications of ASO and RNAi technologies, highlight emerging CRISPR-Cas systems and consider the implications of RNA-targeting therapeutics in the development of future drugs to treat eye disease.     

眼球表面鳞状细胞肿瘤107例临床分析

为探讨眼球表面鳞状细胞肿瘤（Ｏｃｕｌａｒｓｕｒｆａｃｅｓｑｕａｍｏｕｓｎｅｏｐｌａｓｉａ，ＯＳＳＮ）的分型及临床特点。对赞比亚恩多拉中心医院眼科门诊１０７例眼球表面鳞状细胞肿瘤进行回顾性分析。结果：在１０７例眼球表面鳞状细胞肿瘤中，结角膜上皮内肿瘤（Ｃｏｎｊｕｎｃｔｉｖａｌａｎｄｃｏｒｎｅａｌｉｎｔｒａｅｐｉｔｈｅｌｉａｌｎｅｏｐｌａｓｉａ，ＣＩＮ）５３例，鳞状细胞癌（Ｓｑｕａｍｏｕｓｃｅｌｃａｒｃｉｎｏｍａ，ＳＣＣ）５４例，在ＣＩＮ中，非典型增生（Ｄｙｓｐｌａｓｉａ）４４例，原位癌（Ｃａｒｃｉｎｏｍａｉｎｓｉｔｕ）９例，在ＳＣＣ中，４例侵犯眼球或眼眶。患者多为年轻人，年龄最小１４岁，最大６２岁，平均年龄ＣＩＮ为３４岁，ＳＣＣ为３６岁。女性略多于男性，病变多为早期，较少侵犯眼内。结论：该肿瘤为赞比亚常见眼病，年轻患者多，紫外线照射和感染可能是其主要发病因素；早期诊断、早期手术是治疗本病的关键     

ACE2 and TMPRSS2 are expressed on the human ocular surface,suggesting susceptibility to SARS-CoV-2 infection

PurposeConjunctival signs and symptoms are observed in a subset of patients with COVID-19, and SARS-CoV-2 has been detected in tears, raising concerns regarding the eye both as a portal of entry and carrier of the virus. The purpose of this study was to determine whether ocular surface cells possess the key factors required for cellular susceptibility to SARS-CoV-2 entry/infection.MethodsWe analyzed human post-mortem eyes as well as surgical specimens for the expression of ACE2 (the receptor for SARS-CoV-2) and TMPRSS2, a cell surface-associated protease that facilitates viral entry following binding of the viral spike protein to ACE2.ResultsAcross all eye specimens, immunohistochemical analysis revealed expression of ACE2 in the conjunctiva, limbus, and cornea, with especially prominent staining in the superficial conjunctival and corneal epithelial surface. Surgical conjunctival specimens also showed expression of ACE2 in the conjunctival epithelium, especially prominent in the superficial epithelium, as well as weak or focal expression in the substantia propria. All eye and conjunctival specimens also expressed TMPRSS2. Finally, Western blot analysis of protein lysates from human corneal epithelium obtained during refractive surgery confirmed expression of ACE2 and TMPRSS2.ConclusionsTogether, these results suggest that ocular surface cells including conjunctiva are susceptible to infection by SARS-CoV-2, and could therefore serve as a portal of entry as well as a reservoir for person-to-person transmission of this virus. This highlights the importance of safety practices including face masks and ocular contact precautions in preventing the spread of COVID-19 disease.     

Importance of the intestinal microbiota in ocular inflammatory diseases: A review

The purpose of this article is to review the literature on relationships between the intestinal microbiota and ocular inflammatory disease, specifically non‐infectious uveitis and age‐related macular degeneration. The importance of the intestinal microbiota in uveitis pathogenesis has been shown by multiple groups demonstrating that alterations in the microbiota induced by certain oral antibiotics results in reduced uveitis severity, and another group demonstrating that a commensal intestinal bacterial antigen activates retina‐specific autoreactive T cells, potentially indicating a commensal trigger for uveitis. Additionally, commensal intestinal bacterial metabolite short chain fatty acids can be utilized to suppress autoimmune uveitis. Age‐related macular degeneration is associated with intestinal dysbiosis, which is partially influenced by genetic risk alleles and AREDS supplementation. Strategies for therapeutically targeting the intestinal microbiota might involve several approaches, including the use of antibiotics, dietary changes, drugs that supplement beneficial bacterial metabolites or target causative bacterial strains, dietary strategies or faecal microbial transplantation. In summary, the intestinal microbiota are at the cross‐roads of genetic and environmental factors that can promote ocular conditions such as non‐infectious uveitis and age‐related macular degeneration, partially via its dynamic influence on mucosal and systemic immunity. The intestinal microbiome thus represents a salient potential target for therapeutic modulation to treat these potentially blinding conditions.     

Aqueous humor induces lymphatic regression on the ocular surface

PurposeThis study is to investigate the potential effect of aqueous humor on already formed lymphatic vessels of the ocular surface including the conjunctiva and the cornea.MethodsAqueous humor harvested from fresh bovine or murine eyeballs were used in the study. It was injected into the subconjunctival space of Prox-1-GFP (green fluorescent protein) transgenic mice. Pre-existing conjunctival lymphatics were observed in vivo using our advanced live imaging system. Additionally, ex vivo tissue cultures were performed in aqueous humor with normal conjunctival tissues or inflamed corneas with newly formed lymphatic vessels. Time lapse images were taken by an advanced live cell imaging system with an incubator. Moreover, human primary microdermal lymphatic endothelial cell culture system was employed to evaluate the effect of aqueous humor on lymphatic tube regression in vitro.ResultsAqueous humor induced lymphatic regression in both normal conjunctiva and inflamed corneas. It also led to the regression of formed lymphatic tubes by the lymphatic endothelial cells in vitro.ConclusionsThis study provides the first direct and real time live imaging evidence showing that aqueous humor induces lymphatic regression. Further investigation promises for divulging new mechanisms and therapeutic strategies to treat lymphatic diseases that occur both inside and outside the eye.     

有无睑板腺功能障碍患者眼表菌群组成对比

目的 研究睑板腺功能障碍(MGD)与非MGD(NMGD)患者的眼表菌群的组成及差异.方法 招募了57例MGD患者为MGD组,32名健康志愿者为NMGD组,对两组受试者结膜拭子进行16S rRNA基因V3-V4片段的高通量测序,对测序数据进行生物信息学分析,以研究MGD组患者和NMGD组受试者眼表菌群的组成及差异.结果 ...     

Effects of perioperative managements on ocular surface microbiota in intravitreal injection patients

AIM:To investigate the effects of on ocular surface microbiota in patients who received intravitreal injections.METHODS:Samples of ocular surface microbiota were obtained from 41 eyes of 41 patients who visited the Department of Ophthalmology.Patients were separated for three groups.Group A did not receive perioperative managements or intravitreal injection.Group B1 received only once and B2 received more than twice.In operating room,the samples were collected on the ocular surface.Operating taxonomic units(OTUs) clustering and alpha/beta diversity analysis was performed.The microbial 16S rRNA from samples were analyzed using the Hi Seq 2500 platform.RESULTS:Alpha diversity did not differ in each group,and beta diversity differed in the B2 group.Beta diversity showed a significant difference between Group A and B2(P=0.048).With the perioperative managements before intravitreal injection,the composition and relative abundance were altered.Top 10 microbiota on phylum and genus level,and then microbiota notably changed at genus level were listed.Gram-negative bacteria were varied more.Furthermore,Proteus was not found in Groups A and B1,but it was appeared after the patients received perioperative management and intravitreal injections in Group B2.CONCLUSION:With the perioperative managements,the balance of microbiota on the ocular surface is destroyed,and relative composition and abundance of microbiota on the ocular surface is obviously altered.The clinical doctors should pay more attention on the consequence of perioperative managements before intravitreal injection.     

The impact of diabetes on corneal nerve morphology and ocular surface integrity

Diabetes mellitus is a chronic disease that results from inadequate insulin production or ineffective insulin utilization. It is one of the most common systemic diseases worldwide with increasing prevalence. Diabetes mellitus is associated with premature mortality, macrovascular complications such as cardiovascular disease, and microvascular complications, including nephropathy leading to kidney failure, potentially blinding diabetic retinopathy, and diabetic neuropathy. While the retinal complications of diabetes are well recognized by eye care professionals, the effects on the ocular surface are poorly understood. Recent studies have reported on the association between peripheral neuropathy and corneal neuropathy, showing the latter to be of predictive value for the systemic disease. Corneal neuropathy can lead to loss of corneal sensation and can ultimately result in neurotrophic ulcers and significant visual morbidity. The epithelial fragility and poor wound healing that result from reduced epithelial adhesion to the underlying basement membrane in diabetes, together with corneal neuropathy, are thought to increase the susceptibility to persistent corneal erosions and infection, as well as to increase the risk of post-surgical complications. The aim of this article is to review the impact of diabetes on corneal nerve morphology and ocular surface integrity. Changes in the tear film and ocular surface microbiome are highlighted in discussion of the mechanisms that underpin ocular surface changes that increase the susceptibility to corneal erosion and infection.     

人眼表微生物群与眼表疾病研究进展

眼表微生物群是人体眼表微环境的一部分,在维持其稳定中占据重要作用。许多研究对于健康与疾病状态下眼表微生物群的组成进行探究,但研究结果基于内外因素的不同而存在差异,且微生物失调与疾病之间的关系也尚未明确。近年来,随着肠道微生物与全身性疾病的研究不断深入,眼科研究者们也从中获得了一些启发,对眼表微生物群与眼表非感染性疾病的关系有了更进一步的探讨。本文将对正常眼表核心微生物群、眼部及全身性疾病眼表微生物群的变化进行综述,并讨论微生物失调引起疾病的可能机制,希望对未来眼表微生物群的进一步研究提供参考依据。     

The impact of anticancer drugs on the ocular surface

Cancer is a global health problem and is one of the leading causes of death worldwide. Pleasingly, the rate of survival has improved and continues in an upward trend mainly due to better diagnosis and treatment modalities. In particular, the development of anticancer drugs including cytotoxic chemotherapy, hormonal agents and targeted therapies have provided the most effective treatment options in combatting cancerous cells. However, the antineoplastic mechanisms of these drugs can also lead to undesirable systemic and ocular side effects resulting from cytotoxicity, inflammation and neurotoxicity. While survival rates are projected to increase with time, the number of patients presenting with these side effects that can substantially impact quality of life will also rise. The current paper reviews the ocular surface and adnexal side effects of anticancer drugs, the appropriate management and possible interactions between drugs for ocular surface pathology treatment and the anticancer drugs.     

CT检查在眼外伤中的临床应用价值

目的探讨cT检查在眼外伤中临床应用价值。方法回顾分析52例（84眼）急诊眼外伤的CT检查资料。结果52例（84眼）CT检查均发现异常,包括眶内异物、眼内异物、眶骨骨折、眶内软组织伤、晶状体脱位、晶状体脱出、眼球变形和复合性损伤等。结论CT是眼外伤的首选检查方法,可为临床诊断和手术提供重要依据。     

Time course of ocular surface and lacrimal gland changes in a new scopolamine-induced dry eye model

Background The aim of this study was to set up an animal model of dry eye showing disturbance in several components of the lacrimal functional unit, and to describe the time course of the appearance of clinical signs and inflammatory markers. Methods Dry eye was induced in 6-week-old female Lewis rats by a systemic and continuous delivery of scopolamine via osmotic pumps implanted subcutaneously. We first determined the appropriate dose of scopolamine (6, 12.5, or 25 mg/day) for 28 days. In a second set of experiments, we determined markers after 1, 2, 3, 7, 10, 17, or 28 days of a 12.5-mg/day dose. Clinical signs of corneal dryness were evaluated in vivo using fluorescein staining. MHC II expression and mucin Muc5AC production were detected on the conjunctival epithelium using immunostaining. The level of IL-1β, IL-6, TNF-α, and IFN-γ mRNA was evaluated by real-time polymerase chain reaction in conjunctiva and exorbital lacrimal gland (LG). Lipids were extracted from the exorbital LG for fatty acid analysis. Results Daily scopolamine doses of 12.5 mg and 25 mg applied for a 28-day period induced keratitis, a decrease in Muc5AC immunostaining density in the conjunctival epithelium, and modifications in the fatty acid composition of the exorbital LG. Animals treated with a 12.5-mg/day dose of scopolamine exhibited an increase in corneal fluorescein staining after 2, 10, and 28 days. All animals exhibited unilateral or bilateral keratitis after 17 days. In the conjunctival epithelium, a significant decrease in Muc5AC immunostaining density was observed at early and late time points, and MHC II expression tended to be increased after 1, 7, 10, and 28 days, without reaching statistical significance. The levels of TNF-α, IL-1β and IL-6 mRNA were increased with scopolamine treatment in both conjunctiva and exorbital LG. Arachidonic acid and the Δ5 desaturase index were significantly increased in the exorbital LG of dry eye animals at each time point. Conclusions This systemic and continuous scopolamine-induced model of dry eye in the rat may represent a helpful tool to investigate moderate dry eye, and makes a contribution in the field of dry eye study. Support The PhD fellowship of S. Viau was in part supported by a grant from the Regional Council of Burgundy.     

The first case of keratitis caused by <Emphasis Type="Italic">Nocardia exalbida</Emphasis>

Background Nocardia exalbida was first reported in 2006. We describe a first case of keratitis caused by Nocardia exalbida. Methods Case report Results A patient presented after two weeks of unsuccessful treatment of a corneal ulcer in her right eye. Nocardia keratitis was diagnosed from her culture results, and the species Nocardia exalbida was determined by phylogenetic studies using gene sequence analysis of 16S RNA. The disk diffusion method showed that this Norcardia sp. was sensitive to many antibiotics. Initially, the patient was treated with topical and systemic antibiotics, and corneal epithelium quickly regenerated. But when corticosteroid eyedrops were added, there was a recurrence of the keratitis. Corticosteroids were stopped, and systemic trimethoprim-sulfamethoxazole and topical tobramycin, colistin, chloramphenicol and sulfisoxazole were given. Within one month the corneal ulcer and infiltration disappeared. Conclusion This is the first report of keratitis caused by Nocardia exalbida. This species is susceptible to many antibiotics in vitro and clinically. However, supplementation with corticosteroids can lead to recurrence, and care should be taken when corticosteroids are being considered.     

儿童眼外伤297例临床分析

目的分析儿童眼外伤的常见原因、临床特点,为积极预防提供健康教育知识。方法对近5年我院收治的儿童眼外伤患者297例的性别、年龄、受伤原因、性质、并发症、视力变化等进行回顾性总结分析,探索有效的防治途径。结果 297例(307只眼)儿童眼外伤中,男孩多于女孩,多发于学龄前期年龄组,致伤性质以钝器伤、锐器伤以及爆炸伤多见,致盲率为17.86%。结论儿童眼外伤严重地影响着儿童的视功能,并发症多,预后不良,因此重在预防。     

Transient reduction of the ocular perfusion pressure and the oscillatory potentials of the ERG

PURPOSE: To evaluate the changes of the Oscillatory Potentials (OPs) of Electroretinogram (ERG) caused by short-term hypertension in human subjects, and their relationship with ocular perfusion pressure (OPP). METHODS: Suction cup technique in 12 normal volunteers with OPs simultaneously recording. RESULTS: Scotopic and photopic OPs were altered during OPP drop. Scotopic OPs showed more sensitiveness, with higher reduction (from 21% to 47%), when compared to the basal value, than in photopic recordings (from 14% to 34%). In both conditions, the relationship between OPP and OPs presented a steady amplitude before the trough after the +30 step, and rapid recovery after OPP normalisation. ANOVA and correlation analysis confirmed the data. CONCLUSION: The ERG OPs seemed to reflect the OPP modification. The features of OPs amplitudes suggest involvement of the retinal autoregulation mechanism and support development for further clinical studies.     

静脉用环丙沙星在开放性眼外伤眼内渗透性研究

目的 探讨在开放性眼外伤患者单剂量静脉滴注环丙沙星的眼内渗透性.方法 选择16例非化脓开放性眼外伤和12例住院白内障手术为正常对照的患者,单次静脉滴注环丙沙星注射液200mg后1h抽取少许房水和玻璃体,采用高效液相色谱法检测眼内环丙沙星浓度,双缩脲法检测房水蛋白含量. 结果正常对照组的房水蛋白含量是(0.067±0.037)g/L,开放性眼外伤组是(6.482±2.981)g/L,开放性眼外伤组的房水蛋白含量明显高于正常对照组,P<0.05.在对照组房水中环丙沙星浓度是(0.158±0.035)μg/ml,开放性眼外伤组房水中环丙沙星浓度是(0.175±0.142)μg/ml,开放性眼外伤组与对照组相比P>0.05,浓度差异无统计学意义.开放性眼外伤组玻璃体中环丙沙星浓度(0.082±0.022)μg/ml,环丙沙星在眼内不能达到眼内炎常见致病菌的体外90%最小抑菌浓度((MIC90).结论 在开放性外伤眼的血房水屏障破坏,但环丙沙星眼内渗透性并没有增强,单剂量静脉滴注后不能在眼内达到有效的抑菌浓度,在围手术期用药不能达到预期的抗菌效果.     

保存人羊膜移植治疗难治性眼表疾病的临床效果

目的　探讨保存人羊膜移植治疗难治性眼表疾病的临床效果。方法　采用保存人羊膜移植治疗 49例 5 6眼难治性眼表疾病 ,其中翼状胬肉 2 6例 3 3眼 ,急性碱烧伤 3例 ,慢性化学性烧伤13例 ,大泡性角膜病变 4例 ,眼表良性肿瘤 3例。结果　术后无一例眼发生感染 ,除一例急性碱烧伤患者于术后第 5天羊膜溶解、脱落外 ,其余患者术后羊膜植片平伏 ,术后 1～ 4周内正常上皮沿羊膜表面生长 ,成功重建眼表。经过平均 11 2± 5 6个月的随访观察 ,翼状胬肉者中 5眼复发 ,手术成功率为 84 8% ,复发率为 15 2 % ,3例急性碱烧伤者出现角膜结膜化 ,未能获得长期稳定的眼表 ,慢性化学性烧伤者角膜新生血管明显减轻 ,睑球粘连松解 ,视力有不同程度改善 ,大泡性角膜病变者主观症状得以改善 ,眼表良性肿瘤者未见复发及并发症发生。结论　保存的人羊膜移植能安全、有效地重建部分难治性眼表疾病患者的眼表 ,但对急性严重碱烧伤患者的远期疗效不理想。